a/
\(\Leftrightarrow2-5x\le3\left(2-x\right)+5\)
\(\Leftrightarrow2-5x\le6-3x+5\)
\(\Leftrightarrow-5x+3x\le6+5-2\)
\(\Leftrightarrow-2x\le9\)
\(\Leftrightarrow x\ge\dfrac{-9}{2}\)
b/
\(\Leftrightarrow2\left(x-3\right)-5\ge0\)
\(\Leftrightarrow2x-6-5\ge0\)
\(\Leftrightarrow2x-11\ge0\)
\(\Leftrightarrow x\ge\dfrac{11}{2}\)